(1) Field of the Invention
The present invention relates to a method of treating grafted fiber or fibrous material.
(2) Description of the Prior Art
It is known that a water-soluble vinyl monomer is graft-polymerized to fiber or fibrous material (hereinafter, fiber and fibrous material are merely referred to as fibrous material) having active hydrogen to give permanent sweat absorbing property, hygroscopicity, antistatic property and the like to the fibrous material. However, in the grafted fibrous material, the grafted branched chain changes the properties of the surface of the fibrous material, and when synthetic fiber, such as polyamide fiber or the like, is grafted, slimy feeling peculiar to synthetic fiber decreases or disappears. While, when white fabric is grafted, the surface of the grafted white fabric appears dark due to the irregular reflection of light on the surface. The change of color of fibrous material surface due to the grafting of the fibrous material appears more significantly by the after-treatments, such as fluorescent whitening, dyeing, softening treatment, antistatic treatment and the like, and as the result, the color matching of the above treated fibrous material becomes very difficult.
The inventors have made various investigations in order to prevent the change of color of grafted fibrous material during the above described after-treatments, and found that the change of color can be remarkably decreased by treating the grafted fibrous material with a specifically limited processing agent before the above described after-treatments or with a mixture of the processing agent and other treating agent at the above described after-treatments, and accomplished the present invention.